Update .gitattributes to modify export-ignore

Remove phpunit.xml from export-ignore list

Author: WizardLoop

.gitattributes

@@ -11,7 +11,6 @@
 *.env text
 
 # Exclude tests and dev files from export
-phpunit.xml export-ignore
 phpcs.xml export-ignore
 php-cs-fixer.dist.php export-ignore
 .dockerignore export-ignore